Absorbent materials in the form of relatively dense sheet-like structures resembling heavy weight paper, blotter paper or paperboard are referred to as absorbent boards. This terminology distinguishes such absorbents from loose, bulky materials such as wood pulp, fluff and the like. Absorbent boards may be formed of a variety of materials of natural and/or synthetic origin. For example, absorbent boards may be prepared from wood pulp, peat moss and mixtures thereof, optionally including other components such as reinforcing synthetic textile fibers, natural fibers, binders, surfactants and the like. Such boards are commonly prepared by wet laying a slurry of the solid components of the board on conventional papermaking equipment.
For example, U.S. Pat. No. 4,507,122 discloses a laminate structure comprising a thin layer of kraft paper and a heavier layer of a mixture of peat moss and wood pulp. The materials are sequentially deposited from an aqueous slurry in a wet process on conventional paper making equipment. The deposited solids are dewatered, partially dried and compressed to a density from about 0.2 to 1.0 g/cc. The resulting absorbent board is relatively stiff, and flexibility may be increased by mechanical working such as embossing microcreping or micro-corrugating. The reference suggests that the flexibility of the board may also be increased by slitting.
The present invention is concerned with a novel apparatus for improvement of an absorbent structure composed of peat moss, wood pulp, mixtures thereof or other compacted friable absorbent material. The apparatus provides increased flexibility in at least one direction to absorbent boards.